Demographic details of patients and controls

<p>Age, sex and race matched controls were compared to medicated schizophrenia patients and a set of minimally medicated and unmedicated schizophrenia patients for proliferation assays. T cells from minimally medicated and unmedicated patients were also used to assess differential gene expression by microarray and for flow cytometric analysis of cell surface marker expression. Ages are expressed as mean ± standard deviation. Patients with recent substance abuse were excluded from the study.</p

Genes significantly altered between patient and control T cells map to known schizophrenia susceptibility loci.

<p>A heat map was generated in order to identify the chromosomal location of significantly differentially expressed genes from patient and control T cells. Clusters of significantly altered genes between SZ and C freshly isolated T-cells were found at 1p36, 1q42, 4q12, 6p22, 9q22, 10q26. 1p36, 1q42 and 6p22 are strong susceptibility loci</p

Patients with schizophrenia show lower proliferative responses to stimulation with anti-CD3.

<p>(A) Medicated schizophrenia patients were found to have significantly lower proliferative responses to <i>in vitro</i> stimulation compared to healthy controls at all concentrations of stimulation with anti-CD3. (B) T cell proliferation was also measured in minimally medicated and unmedicated patients to rule out the possibility of drug effect. These also showed significantly lower proliferative responses to stimulation.</p

Functional pathways associated with cell cycle, cell signalling and oxidative stress and metabolism were significantly altered in schizophrenia by microarray analysis of gene expression.

<p>Onto-Express was used for pathway analysis of significantly altered genes by identifying gene ontology (GO) categories that are over-represented in the list of significant genes relative to the representation on the array. Five categories associated with cell cycle were found to be significantly involved, including cell cycle (p = 0.0005), cell cycle arrest (p = 0.0007), negative regulation of cell cycle (p = 0.001), mitosis (p = 0.005) and regulation of cell cycle (p  =  0.039).</p><p>Four categories associated with cell signalling were found to be significantly altered, including signal transduction (p = 0.0009), cell-cell signalling (p = 0.012), protein amino acid phosphorylation (p = 0.015) and intracellular signalling cascade (p = 0.050).</p><p>Three categories involved in oxidative stress were found to be significantly altered, including response to oxidative stress (p = 0.0003), electron transport (p = 0.001) and metabolism (p = 0.013).</p

Patient and control T cells show similar levels of CD3 and TCRαβ expression before and after stimulation.

<p>(A) CD3 Expression was measured by flow cytometry on patient and control T cells before and after stimulation with anti-CD3. There was no significant difference in the level of expression between patients and controls. (B) Expression of TCR αβ chains on the surface of T cells was also comparable between patients and controls before and after stimulation.</p

Lower T cell proliferation in schizophrenia does not result from deficient IL-2 production, or receptor expression.

<p>(A) IL-2 production was measured in supernatants from patient and control T cells stimulated with 0 µg/ml, 0.01 µg/ml, 0.1 µg/ml and 1 µg/ml OKT3. There was no significant difference in production of IL-2 between patients and controls at each concentration of OKT3. (B) The percentage of CD25+ CD4+ and CD8+ T cells was similar between patients and controls before and after stimulation and there was no significant difference in level of expression of CD25 before or after stimulation (C).</p